This disclosure is generally directed to toner processes, and more specifically, emulsion aggregation and coalescence processes, as well as toner compositions formed by such processes and development processes using such toners.
Emulsion aggregation/coalescing processes for the preparation of toners are illustrated in a number of Xerox patents, such as U.S. Pat. Nos. 5,290,654, 5,278,020, 5,308,734, 5,370,963, 5,344,738, 5,403,693, 5,418,108, 5,364,729, and 5,346,797; and also of interest may be U.S. Pat. Nos. 5,348,832; 5,405,728; 5,366,841; 5,496,676; 5,527,658; 5,585,215; 5,650,255; 5,650,256 5,501,935; 5,723,253; 5,744,520; 5,763,133; 5,766,818; 5,747,215; 5,827,633; 5,853,944; 5,804,349; 5,840,462; 5,869,215; 5,863,698; 5,902,710; 5,910,387; 5,916,725; 5,919,595; 5,925,488 and 5,977,210. Other patents disclosing exemplary emulsion aggregation/coalescing processes include, for example, U.S. Pat. Nos. 6,730,450, 6,743,559, 6,756,176, 6,780,500, 6,830,860, and 7,029,817.
The disclosures of each of the foregoing patents and publications are hereby incorporated by reference herein in their entireties. The appropriate components and process aspects of the each of the foregoing patents and publications may also be selected for the present compositions and processes in embodiments thereof.
In a number of electrophotographic engines and processes, toner images may be applied to substrates. The toners may then be fused to the substrate by heating the toner with a contact fuser or a non-contact fuser, wherein the transferred heat melts the toner mixture onto the substrate. Electrophotographic digital printing with current toners can produce a range of print gloss when fused using contact fusers such as rolls or belt based fusing sub-systems. The desired gloss level depends on specific customer applications.
To date, toners that are fused with non-contact fusing sub-systems such as flash fusing, radiant fusing or steam fusing sub-systems produce prints that are matte or require very long (2 second) dwell times. Moreover, non-contact fusing systems sometimes utilize high speed continuous feed systems. At high print speeds, colored toners (cyan (C), magenta (M) and yellow (Y)) have lower light-absorbing capacity than a black toner (carbon black absorbs energy), and thus fail to absorb sufficient light to convert energy into heat, resulting in insufficient melting or fixing in the fusing step. A gloss difference between color toners and black toners may also occur due to different light-absorbing capacities of different pigments.
Simply increasing emission intensity of a photo-fixer may generate excessive heat from a black toner as a result of absorbing an excessive quantity of light, causing printing defects referred to as voids or toner bursts on the image. When emission intensity during the fusing step is lowered to an extent to avoid formation of voids by the black toner, insufficient melting or resin flow of the color toners, especially magenta and yellow toners, may be observed. This is because the magenta and yellow toners, which have lower visible light absorbing capacity than a black or cyan toner, cannot absorb sufficient light to melt or cause resin flow.
Toners that are fixed to paper with non-contact fusing having high print gloss with short dwell times remain desirable.